Since Courage the Cowardly Dog premiered in 1999, the show has filled our daydreams and nightmares with terrifying imagery and existential dread. Set in the middle of Nowhere, Kansas, Courage follows the titular little purple dog as he tries to protect his owners, Muriel and Eustace Bagge, from the dangerous (and sometimes misunderstood) forces that find their way to their isolated farmhouse. The show’s unique, mixed-media art style and references to classic horror made Courage stick in the trauma centers of our brains.

For many, Courage was an introduction to the aesthetic and conceptual possibilities of the horror genre; this dog was our guide to newfound horrors, letting us know that it’s okay, even normal, to be scared. And while most of us have likely found new frights to fill our nightmares, the kernels of those chilling visuals, eerie sounds, and unnerving concepts from Courage still live in the recesses of our minds. Every episode was scary in some way, but these are some of the scariest.

“The Clutching Foot” sees Courage dealing with the subgenre of body horror. Eustace gets a foot fungus that rapidly expands, enveloping the farmer’s entire body and transforming into a giant, hideous purple foot. And this fungus foot isn’t just alive, it’s sentient: a walking, talking gang of five led by the one and only Big Toe. Big Toe and the gang threaten to squish Muriel, forcing Courage to commit crime in their stead.

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Seeing Eustace’s body completely overwhelmed by the fungus feels like something straight out of Cronenberg. The episode quite possibly introduced kids everywhere to the fundamental concept of body horror; namely, the complete loss of bodily self to something else. Eustace’s fungus may not have been the abject nightmare of, say, The Fly, but it certainly felt like it at the time.

19 The Quilt Club

“The Quilt Club” is one of the aesthetically darker episodes of Courage, featuring dingy, monotone background elements and a haunting organ theme. Muriel and Courage meet Elisa and Eliza Stitch, the conjoined twins who run the local craft shop. Muriel grows obsessed over making samples that will earn her spot in the twins’ exclusive quilt club, forgoing her household duties and even forgetting Eustace and Courage.

The Stitch Sisters finally accept Muriel, which Courage discovers is a trap: the “club” is the sisters’ quilt itself, a vessel that traps the souls of its members inside to feed Elisa and Eliza’s everlasting lives. Courage destroys the quilt by reminding Muriel of her family, which in turn transforms the Stitch Sisters into a piece of fabric. The concept of Muriel being trapped in the quilt is terrifying enough for a kid, but the fact that she chose to put herself in the situation specifically to “fit in” is the more existential scare here.

18 Feast of the Bullfrogs

In “Feast of the Bullfrogs” a group of giant bullfrogs, led by King Bufo invade the Bagge household to make it their new pond. Under the threat of violence, the frogs get their way. Eventually, they even force Muriel and Eustace to behave like frogs living in their pond. This isn’t the end of it, as Bufo wants to eat his new wards in a celebratory feast.

Of course, Courage manages to save his owners through a mixture of wit and cartoon shenanigans. What’s especially scary about this episode is the way in which Bufo and crew strong-arm the Bagges into being frogs, even to the point where they can only “speak” in croaks.

17 Night of the Weremole

As the title suggests, “Night of the Weremole” is a play on classic werewolf stories. While tending her garden, Muriel is bitten by the eponymous weremole and eventually turns into a ferocious beast herself. Dr. Vindaloo is of no help, instead getting attacked by Muriel and later transforming himself. The plot of this episode is exceedingly simple, but Muriel’s appearance as the monster is undeniably freaky. This is one of the many Courage episodes that end on a cliffhanger featuring Eustace in peril, under attack by the transformed Vindaloo.

16 Evil Weevil

We all like to think that we’d help someone in need, but “Evil Weevil” makes viewers wary of that practice. In the episode, Eustace accidentally hits a humanoid fly with his truck. Muriel insists on bringing the bug to their home and treating him to dessert as an apology for the accident. But what starts as a simple conversation — albeit, with a bug-man — over dessert quickly turns sinister when Courage notices the bug sucking Eustace and Muriel literally dry. That concept is itself nightmarish, but what’s worse is that Muriel and her family are cosmically punished for doing a good thing. It’s enough to make any kid think twice about helping out a stranger.

15 The Shadow of Courage

One of the earliest episodes of the series, “The Shadow of Courage” exemplifies a staple of the series and its villains. When an old scientist suddenly dies, his shadow is free to wander Nowhere and scare the locals before he himself is scared into fleeing to the Bagge farmhouse. The shadow torments the family throughout the night, even making Eustace flee to the safety of his pickup truck. Without any other options, Courage has a conversation with the shadow, who tells him that his real dream is to become the shadow of a star. He instead becomes the shadow of the stars in the sky on Courage’s recommendation.

The shadow’s impersonations are scary, even sometimes violent. To scare Courage, the shadow depicts Muriel getting decapitated, cut in half with a circular saw, burned on a pyre, and more. Even so, the shadow isn’t without redemption. Like many of the show’s villains, the shadow is only villainous because he’s misunderstood.

14 Windmill Vandals

“Windmill Vandals” of one of the few episodes of Courage where the threat is acknowledged and resolved by all three members of the Bagge family. The episode tells the story of the legendary Windmill Vandals that plagued the town of Nowhere 250 years prior and of their defeat at the hands of the farmer who built the Bagge home, Jiles Galette.

Using magical runes on his windmill, Galette kept the Vandals at bay so long as the mill kept spinning. When it stops in the present day, the Vandals return as skeleton warriors, complete with skeletal horses and realistic weaponry like swords and axes. Unlike many of the more stylized villains in Courage, the Vandals have a more realistic appearance that makes them feel like a different kind of threat.

13 Everyone Wants to Direct

When famed director Benton Tarantella comes knocking on the farmhouse door, Muriel and Eustace can’t help but be starstruck by the possibility of fame and fortune. So much so, that they don’t notice that the director is clearly a zombie. The two are eager to help Tarantella in every way, but Courage quickly discovers that Tarantella and his former partner, Errol Von Volkheim, were serial killers who disguised themselves as directors to lure in their victims. Tarantella died in prison, but Von Volkheim was released and, when he died, was buried directly beneath the farmhouse.

The zombie designs are creepy, but what’s really jarring about this episode is hearing about, in a children’s show, serial killers who murdered 12 people. Courage wasn’t the only show at the time to explore horror in children’s media, but it may be one of the only to have a verified body count.

12 Car Broke, Phone Yes

The setup to “Car Broke, Phone Yes” is classic sci-fi horror. After Courage sees an asteroid land near the farmhouse, a mysterious stranger comes knocking at the door. He’s a small man in a large trench coat and hat, nothing but his bulging eyes showing beneath the getup. When he speaks, the man only says, “Car broke, phone yes?”, but he doesn’t even know how to use the phone.

Courage discovers the man is an alien — just a brain, two eyes, and two tentacles — probing for kindness and indeed stealing all of Muriel’s away. Distraught at the idea of living with two unkind owners, Courage must defeat the alien to return Muriel to her usual self. This is another episode that makes you think twice about showing kindness to strangers. Once again, Muriel is punished for doing the “right” thing, while Eustace is temporarily rewarded for his cruelty.

11 Queen of the Black Puddle

The episode “Queen of the Black Puddle” is probably the most selfless we see Courage act in the series, and that says a lot. In it, Eustace is seduced by the eponymous Queen, a siren-like creature who dwells within water’s reflection. The Queen easily takes Eustace into her realm, where she plans to eat him. Muriel is devastated at the loss of her husband, and Courage, out of his love for her, rescues Eustace.

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The Queen is beautiful in a Morticia Addams sort of way until she transforms into a hideous fish monster intent on devouring the farmer. And it’s very clear that that’s what she’s doing, considering the skeletons littering her lair’s floor. Courage didn’t have to go through all this, but, as the catchphrase goes, “The things I do for love.”

10 The Great Fusilli

“The Great Fusilli” taps into the very real fear of losing complete control of yourself to another. Similar to “Everyone Wants to Direct,” this episode has Muriel and Eustace taken in by a conman with the promise of fame and fortune. This time, it’s an alligator by the name of the Great Fusilli who offers the Bagges parts in his traveling stage show. This is no ordinary stage show, however; it’s a marionette show, and Fusilli wants to add the Bagges to his puppet collection. Courage manages to escape the alligator’s clutches, but Muriel and Eustace are transformed into lifeless marionettes. Even after Fusilli is defeated, Muriel and Eustace are puppets; the episode ends with Courage trying to reenact daily life with his newly hollow owners.

As this episode was planned as the series finale, some fans theorize that everything that takes place in the following three seasons of Courage is made up, the delusions of a dog puppeteering his former owners. Or maybe the computer just helped Courage find a cure.

9 The Mask

“The Mask” is one of the creepiest episodes of the series, but it is also one of the thematically darkest and, strangely enough, sweetest. A stranger appears at the farmhouse, as they so often do. This time, it’s a woman in a weird porcelain mask who can’t stop trying to kill Courage out of a hatred for dogs. The woman reveals herself to be Kitty, and that she is drifting after losing her best friend, Bunny, to the abusive gangster Mad Dog. Courage manages to defeat Mad Dog and reunite Kitty and Bunny, with the former conceding that “not all dogs are bad.”

This episode has been lauded by fans not just for the creepiness of Kitty’s mask in the first half, but for its honest depiction of domestic violence. Kitty and Bunny’s relationship is also often interpreted as a romantic one, a theory Dilworth himself confirmed via Twitter.

8 Heads of Beef

There’s nothing like a little cannibalism to traumatize kids into fearing their local burger joint. “Heads of Beef” sees Eustace and Courage trying to find a cheap meal since Muriel is too sick to cook. When they happen upon a diner offering “Burgers, Really Cheap,” it seems too good to be true — maybe, it is. Courage grows suspicious when he finds a face in his burger, and soon thinks he sees the owner’s wife eating another customer’s head.

But, unlike most other episodes of Courage, this one all turns out to be a misunderstanding. Courage’s paranoia, and the viewer’s own, misread the situation by making assumptions about the things they’re seeing. Still, the creepy imagery and implications of cannibalism certainly left some kids with a distaste for hamburgers.

7 Courage in the Big Stinkin’ City

“Courage in the Big Stinkin’ City” is not one of the scariest episodes overall of the series, but that may be precisely what makes its most infamous scene so terrifying. The Bagges arrive in New York City; Muriel is going to perform the sitar at Radio City Music Hall. When they arrive, the family is intercepted by a giant cockroach named Schwick who claims to be a stagehand. Schwick sends Courage on a quest to fetch a mysterious package, which takes the dog to an apartment building full of terrors.

Behind each door lies some monster: King Ghidorah, a shark, and a seemingly normal little girl playing the violin. In a scene reminiscent of Large Marge from Pee-wee’s Big Adventure, the girl rapidly turns around to reveal a screaming claymation face. Jump scares are quite often not scary, but this children’s show has one of the most effective, perhaps because it’s so unexpected.

6 A Night at the Katz Motel

Katz is a reoccurring villain in the series, and “A Night at the Katz Motel” is his introduction. In a clear homage to Pyscho, this episode sees Muriel, Eustace, and Courage forced to find shelter when driving home during a storm. They find the titular motel and meet its owner, Katz, who secretly plans to feed his guests to his collection of giant man-eating spiders.

Katz strikes an imposing figure, and his presence is accompanied by sinister theme music. What’s so especially frightening about him, though, is his sadistic personality: he literally wants to play with his victim before he kills him. Even if, in Courage’s case, that means a game of racquetball, Katz’s demeanor is what sells the scares.

5 Perfect

“Perfect” is the final episode of the series, and quite notably concludes on a hopeful note. In it, Eustace forces Courage to take classes with an elderly schoolteacher who insists upon perfection in everything the dog does. She constantly berates Courage for not being perfect, which causes him to have nightmares about his imperfections.

Many people most clearly remember the nightmare featuring a strange 3D figure ominously informing Courage that “you’re not perfect,” but all the nightmares are uniquely horrifying. Courage is seen in them getting hurt, or worse, hurting the ones he loves, because of his faults. This episode’s focus on the fear of failure is rather mature for young audiences, but its message, that our imperfections are the things that make us uniquely us, is a beautiful one for the series to end on.

4 The Demon in the Mattress

“The Demon in the Mattress” is an episode themed around The Exorcist, so there’s no surprise that it is one of Courage’s most frightening. Instead of Pazuzu, Muriel gets possessed by the demon in her new mattress, which causes her to levitate, spew vomit, and spin her head around completely. Courage even performs an exorcism to relieve Muriel of the demon, though this one is far sillier than anything found in the Bible. This episode is very explicit with its inspiration, meaning the scares were far more intense than kids were prepared for.

3 The House of Discontent

“The House of Discontent” features another of Courage’s most infamous visuals; the giant, glowing white face of the Spirit of the Harvest Moon. Another harvest season has come and nearly gone, and Eustace has yet again failed to grow anything on the farm. The farmer proclaims that he’s done trying to grow anything, which angers the Spirit, causing him to enact chaos around the house.

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The Spirit does everything in its power to rid the farm of the Bagges, including some kitchen trouble in a scene reminiscent of Poltergeist. What people remember being afraid of from this episode is the Spirit itself and for good reason. The live-action head is one of the show’s most uncanny images: the pure white skin, the deep wrinkles, and the abyssal pitch-black eyes make the monster a horrific sight to behold.

2 King Ramses’ Curse

Even people who didn’t watch Courage growing up are probably familiar with “King Ramses’ Curse” because it left such a deep impact on its young audience. A mystical Egyptian tablet has been stolen, and when it ends up in Eustace’s hands all he can think about is how much money the find will net him. Unfortunately for him, Muriel, and Courage, the tablet is cursed, and the spirit of King Ramses sets three plagues upon their home.

The plot of this episode is exceedingly simple, but Ramses CGI design and spooky droning voice proclaiming “Return the slab or suffer my curse” is what stuck in children’s nightmares long into adulthood. That said, the Bagges ought to get better taste in music: Ramses’ jazzy theme is an absolute bop.

1 Freaky Fred

“Freaky Fred” is, without question, one of Courage’s freakiest episodes thanks to the titular character and the unique narration style. “Freaky Fred” tells the story of Muriel’s nephew coming to the farmhouse for a visit through grotesque, sing-song narration that constantly reminds us that Fred has a penchant for being “naughty.” A skinny man with a rictus grin and bearing some threateningly sharp scissors, Fred cuts a nightmarish figure that is absolutely horrifying, even if his greatest crime is just giving bad haircuts.

Given the rise of horror media that plays upon childish aesthetics made creepy, it’s no wonder that “Freaky Fred” would resonate with audiences both past and present.